The first 6 patients enrolled receive regimen A to determine the safety of the initial dose of gemcitabine. After completion of regimen A, cohorts of 3-6 patients receive escalating doses of gemcitabine in regimen B (closed to accrual as of 5/13/03) until the maximum tolerated dose (MTD) is determined. In a separate sequence, cohorts of 3-6 patients receive alternating escalating doses of gemcitabine and paclitaxel in regimen C until the MTD is determined. The MTD is defined as the dose preceding that at which at least 3 of 6 patients experience dose-limiting toxicity.